Java 语言程序设计与数据结构（基础篇）课后练习题 第十三章

public boolean isFilled() {

return filled;

}

public void setFilled(boolean filled) {

this.filled = filled;

}

public Date getDatecreated() {

return dateCreated;

}

public String toString() {

return "Created on: " + dateCreated + "\nColor: " + color + "\nFilled: " + filled;

}

}

package dishisanzhang;

import java.util.Scanner;

public class Triangle extends GeometricObject {

private double side1 = 1.0;

private double side2 = 1.0;

private double side3 = 1.0;

public Triangle() {

}

public Triangle(double side1, double side2, double side3) {

this.side1 = side1;

this.side2 = side2;

this.side3 = side3;

}

public void setSide1(double side1) {

this.side1 = side1;

}

public double getSide1() {

return side1;

}

public void setSide2(double side2) {

this.side2 = side2;

}

public double getSide2() {

return side2;

}

public void setSide3(double side3) {

this.side3 = side3;

}

public double getSide3() {

return side3;

}

public double getArea() {

double result;

double s = (side1 + side2 + side3) / 2;

result = Math.sqrt(s * (s - side1) * (s - side2) * (s - side3));

return result;

}

public double getPerimeter() {

return side1 + side2 + side3;

}

public String toString() {

return "Triangle:side1=" + side1 + "side2=" + side2 + "side3=" + side3;

}

public static void main(String[] args) {

// TODO Auto-generated method stub

Scanner input = new Scanner(System.in);

Triangle triangle = new Triangle();

System.out.print("Enter three sides: ");

double side1 = input.nextDouble();

double side2 = input.nextDouble();

double side3 = input.nextDouble();

triangle = new Triangle(side1, side2, side3);

System.out.print("Enter the color of the triangle: ");

input.nextLine();

String color = input.nextLine();

System.out.print("Enter whether to fill: ");

boolean filled = input.nextBoolean();

triangle.setColor(color);

triangle.setFilled(filled);

System.out.println("Area: " + triangle.getArea());

System.out.println("Perimeter: " + triangle.getPerimeter());

System.out.println("Color: " + triangle.getColor());

System.out.println("Filled: " + filled);

}

}

[](()13.2

=================================================================

package dishisanzhang;

import java.util.ArrayList;

import java.util.Arrays;

public class dishisanzhang {

public static void main(String[] args) {

// TODO Auto-generated method stub

Integer[] n = {1,2,3,4,5,6};

ArrayList<Number> list = new ArrayList<>(Arrays.asList(n));

shuffle(list);

System.out.println(list);

}

public static void shuffle(ArrayList<Number> list){

Number tmp;

for(int i=0;i<list.size();i++){

int tmp1 = (int)(Math.random()*(list.size()));

tmp = list.get(i);

list.set(i, list.get(tmp1));

list.set(tmp1, tmp);

}

}

}

[](()13.3

=================================================================

package dishisanzhang;

import java.util.ArrayList;

import java.util.Arrays;

public class dishisanzhang {

public static void main(String[] args) {

// TODO Auto-generated method stub

Integer[] n = {1, 5, 6, 4, 3, 2};

ArrayList<Number> list = new ArrayList<>(Arrays.asList(n));

sort(list);

System.out.println(list);

}

public static void sort(ArrayList<Number> list){

Number tmp; //下面是一个冒泡排序

for(int i=0;i<list.size()-1;i++)

for(int j=0;j<list.size()-i-1;j++)

if((int)(list.get(j+1))<(int)(list.get(j))){

tmp = list.get(j);

list.set(j, j+1);

list.set(j+1, tmp);

}

}

}

[](()13.4

=================================================================

看清单！

[](()13.5

=================================================================

package dishisanzhang;

import java.util.Date;

public abstract class GeometricObject implements Comparable< GeometricObject >{

private String color;

private boolean filled;

private Date dateCreated;

protected GeometricObject(){

dateCreated = new Date();

}

protected GeometricObject(String color,boolean filled){

this.color = color;

this.filled = filled;

dateCreated = new Date();

}

public String getColor(){

return color;

}

public void setColor(String color){

this.color = color;

}

public boolean isFilled(){

return filled;

}

public void setFilled(boolean filled){

this.filled = filled;

}

public Date getDateCreated(){

return dateCreated;

}

@Override

public String toString(){

return "Create on "+dateCreated+"\nColor: "+color+"\n and Filled"+filled;

}

@Override

public int compareTo(GeometricObject o){

if (getArea() < o.getArea())

{

return -1;

}

else if (getArea() > o.getArea())

{

return 1;

}

else

return 0;

}

public static GeometricObject max(GeometricObject o1,GeometricObject o2){

if (o1.compareTo(o2) > 0)

{

return o1;

}

else

return o2;

}

public abstract double getArea();

public abstract double getPerimeter();

}

package dishisanzhang;

public class Rectangle extends GeometricObject {

private double width;

private double height;

public Rectangle() {

}

public Rectangle(double width, double height) {

this(width, height, "white", false);

}

public Rectangle(double width, double height, String color, boolean filled) {

super(color, filled);

this.width = width;

this.height = height;

}

public double getWidth() {

return width;

}

public void setWidth(double width) {

this.width = width;

}

public double getHeight() {

return height;

}

public void setHeight(double height) {

this.height = height;

}

@Override

public double getArea() {

return width * height;

}

@Override

public double getPerimeter() {

return 2 * (width + height);

}

@Override

public String toString() {

return "\nRectangle Width: " + getWidth() + " and Height: " + getHeight();

}

}

package dishisanzhang;

public class Circle extends GeometricObject {

private double radius;

public Circle() {

}

public Circle(double radius) {

this(radius, "white", false);

}

public Circle(double radius, String color, boolean filled) {

super(color, filled);

this.radius = radius;

}

public double getRadius() {

return radius;

}

@Override

public double getArea() {

return radius * radius * Math.PI;

}

@Override

public double getPerimeter() {

return 2 * radius * Math.PI;

}

@Override

public String toString() {

return "\nCircle Radius : " + getRadius();

}

}

package dishisanzhang;

public class dishisanzhang {

public static void main(String[] args) {

// TODO Auto-generated meth 《一线大厂 Java 面试题解析+后端开发学习笔记+最新架构讲解视频+实战项目源码讲义》无偿开源 威信搜索公众号【编程进阶路】 od stub

Rectangle r1 = new Rectangle(1,2);

Rectangle r2 = new Rectangle(2,3);

System.out.println("The Max: "+GeometricObject.max(r1, r2));

Circle c1 = new Circle(2);

Circle c2 = new Circle(3);

System.out.println("The Max: "+GeometricObject.max(c1, c2));

}